Fabrication and characterization of direct patterning ferroelectric Sr0.9Bi2.1Ta2O9 thin films by photosensitive sol-gel solution

• Published in: Thin solid films 2005-01, Vol.471 (1-2), p.12-18
• Main Authors: LIM, Tae-Young, YANG, Ki-Ho, KIM, Byong-Ho, AUH, Keun-Ho
• Format: Article
• Language: English
• Subjects: Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Liquid phase epitaxy; deposition from liquid phases (melts, solutions, and surface layers on liquids); Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Physics; Surface cleaning, etching, patterning; Surface treatments
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2004.02.102

Photosensitive ferroelectric Sr0.9Bi2.1Ta2O9 (SBT) precursor solutions were synthesized using strontium ethoxide chelated with ethylacetoacetone, tetramethylheptanedionato bismuth and tantalum ethoxide chelated with ethylacetoacetone. SBT thin films with 200 nm thickness were prepared on Pt/TiO2/SiO2/Si substrates using the spin coating method. As UV light exposure time to the SBT thin film increased, the intensity of the UV absorption peak of the metal beta-diketonate decreased due to metal-oxygen-metal bond formation, which led to decreased solubility of SBT thin film. The solubility difference enabled direct patterning of thin films that had ferroelectric properties. The ferroelectric properties of the UV irradiated SBT thin films were superior to those of the non-UV irradiated films. Pr/Ps and 2 Pr values (at 3 V) of SBT thin films improved approximately 8% and 5%, respectively, with UV irradiation.